Where next for delirium research?

New horizons in undergraduate geriatric medicine education

Current projections show that between 2000 and 2050, increasing proportions of older individuals will be cared for by a smaller number of healthcare workers, which will exacerbate the existing challenges faced by those who support this patient demographic. This review of a collection of Age and Ageing papers on the topic in the past 10 years explores (1) what best practice geriatrics education is and (2) how careers in geriatrics could be made more appealing to improve recruitment and retention. Based on these deeper understandings, we consider, as clinician educators, how to close the gap both pragmatically and theoretically. We point out paradigm shifting solutions that include innovations at the Undergraduate level, use of simulation, incorporation of learner and patient perspectives, upskilling professionals outside of Geriatrics and integration of practice across disciplines through Interprofessional Learning. We also identify an education research methodological gap. Specifically, there is an abundance of simple descriptive or justification studies but few clarification education studies; the latter are essential to develop fresh insights into how Undergraduate students can learn more effectively to meet the needs of the global ageing challenge. A case of improving understanding in delirium education is presented as an illustrative example of a new approach to exploring at greater depth education and outlines suggested directions for the future.

Cognitive disorders in advanced Parkinson's disease: challenges in the diagnosis of delirium

Parkinson's disease (PD) is a neurodegenerative condition that is frequently associated with cognitive disorders. These can arise directly from the primary disease, or be triggered by external factors in susceptible individuals due to PD or other predisposing factors. The cognitive disorders encompass PD-associated cognitive impairment (PD-CI), delirium, PD treatment-associated cognitive side effects, cognitive non-motor fluctuations, and PD-associated psychosis. Accurate diagnosis of delirium is crucial because it often stems from an underlying disease that may be severe and require specific treatment. However, overlapping molecular mechanisms are thought to be involved in both delirium and PD, leading to similar clinical symptoms. Additionally, there is a bidirectional interaction between delirium and PD-CI, resulting in frequent concurrent processes that further complicate diagnosis. No reliable biomarker is currently available for delirium, and the diagnosis is primarily based on clinical criteria. However, the screening tools validated for diagnosing delirium in the general population have not been specifically validated for PD. Our review addresses the current challenges in the diagnosis of these cognitive disorders and highlights existing gaps within this field.

Delirium pathophysiology in cancer: neurofilament light chain biomarker - narrative review

Background Delirium is a debilitating disorder with high prevalence near the end of life, impacting quality of life of patients and their relatives. Timely recognition of delirium can lead to prevention and/or better treatment of delirium. According to current hypotheses delirium is thought to result from aberrant inflammation and neurotransmission, with a possible role for neuronal damage. Neurofilament light chain (NfL) is a protein biomarker in body fluids that is unique to neurons, with elevated levels when neurons are damaged, making NfL a viable biomarker for early detection of delirium. This narrative review summarises current research regarding the pathophysiology of delirium and the potential of NfL as a susceptibility biomarker for delirium and places this in the context of care for patients with advanced cancer.Results Six studies were conducted exclusively on NfL in patients with delirium. Three of these studies demonstrated that high plasma NfL levels preoperatively predict delirium in older adult patients postoperatively. Two studies demonstrated that high levels of NfL in intensive care unit (ICU) patients are correlated with delirium duration and severity. One study found that incident delirium in older adult patients was associated with increased median NfL levels during hospitalisation.Conclusions Targeted studies are required to understand if NfL is a susceptibility biomarker for delirium in patients with advanced cancer. In this palliative care context, better accessible matrices, such as saliva or urine, would be helpful for repetitive testing. Improvement of biological measures for delirium can lead to improved early recognition and lay the groundwork for novel therapeutic strategies.

Modifiable risk factors for post-operative delirium in older adults undergoing major non-cardiac elective surgery: a multi-centre, trainee delivered observational cohort feasibility study and trainee survey

BACKGROUND

Post-operative delirium (POD) is an acute brain failure which may occur following major surgery, with serious implications for participants and caregivers. Evidence regarding optimal anaesthetic management for older participants at higher risk of POD is conflicting. We conducted a feasibility study of our protocol in 5 centres to guide sample size estimation and inform future recruitment strategies for a larger cohort study.

METHODS

Participants aged over 65 and scheduled for major surgery were recruited. They were assessed pre-operatively for delirium, cognitive impairment, depression, comorbidity, activity levels and alcohol use. Details of management during surgery, all medications and complications were recorded by a trainee-led research team. Participants were assessed for delirium in the immediate recovery period and then on post-operative days 1-4 using the 4 question attention test (4AT) with complications assessed at day 4 using the post-operative morbidity survey (POMS). Primary outcomes were the incident rates of POD. Secondary outcomes were number of eligible patients, recruitment rates and retention rates throughout the study, time required for data collection, preoperative risk factors assessment and daily postoperative delirium assessments. Also to assess the added value of employing the regional trainee research network (INCARNNET) to deliver the study. Specifically, what proportion of patient consent, data collection and post-operative testing is performed by anaesthesia trainees from this group, especially the success of weekend delirium assessment by trainees? A survey was completed at the end of the study by the trainees involved regarding their involvement in the study.

RESULTS

Ninety-five participants were recruited, of whom 93 completed the study. Overall, POD occurred in 9 patients. Of these, three were detected in recovery and six on post-op days 1-4. Median length of stay was 6 days. Recruitment rates were high in all but one site. 59 (62%) participants were consented by trainees and 189 (63%) of post op delirium assessments were performed by trainees. A total of six patients declined the study (in a follow up survey of trainees). Pre-existing cognitive impairment, depression and problem drinking were detected in 4(4.3%), 3(3.2%) and 5(5.37%) participants, respectively. Co-morbidity was common with 55(59%) in class three or four of the geriatric index of morbidity. Overall, from a total of 641 data points, levels of missing data were as follows, site A = 9.3%, B = 13.5%, C = 15.4%, D = 10.9%, E = 11.1% (data could not be completed retrospectively).

CONCLUSIONS

A multi-centre observational cohort study of delirium carried out by UK trainee anaesthetists is feasible. Patients are content to undergo day of surgery consent and multiple short questionnaires pre-operatively. Proposed data, especially pharmacological, should be carefully considered for their relevance to modifiable mechanisms that can lead to POD. Future research to enable prognostic modelling of POD should involve large scale cohort studies of enriched populations to capture a higher POD incidence. POD remains a common complication in older persons undergoing major surgery in the UK and studies of interventions are urgently needed.

TRIAL REGISTRATION

All methods were carried out in accordance with relevant guidelines and regulations. The study was retrospectively registered with ISRCTN94663125 on 07/02/2018.

Feasibility and potential of a bedside mini-EEG for diagnosing delirium superimposed on dementia

OBJECTIVE

Delirium superimposed on dementia (DSD) is difficult to diagnose because symptoms of delirium might be interpreted as symptoms of dementia. To improve diagnostic accuracy, we investigated the potential of a brief point-of-care EEG measurement.

METHODS

Thirty older patients were included, all with Major Neurocognitive Disorder (i.e. dementia) according to DSM-5 criteria. EEG was registered at right prefrontal and right temporal site, with eyes either open or closed for three minutes, simultaneously with the Discomfort Scale for Dementia of Alzheimer Type. The Confusion Assessment Method for the Intensive Care Unit was administered to determine the presence of symptoms of a delirium at the time of EEG administration. Video registrations were reviewed independently by two delirium experts.

RESULTS

Higher activities of delta and theta1, and lower activities of theta2, alpha, and beta activity, were found in DSD when compared to dementia only. The ratio of delta and theta power during eyes-open conditions had the highest accuracy (AUC = 0.80 [0.63-0.94]; p <.001) to distinguish DSD from dementia alone. All subjects were on benzodiazepines and half on clozapine, thus the effects of psychotropics on EEG cannot be fully excluded.

CONCLUSIONS

A brief point-of-care EEG at two sites of the head has the potential to aid in the detection of DSD.

SIGNIFICANCE

The diagnostic accuracy of EEG in recognizing or excluding delirium in patients who already have dementia is of large potential given the lack of proper diagnostic tools.

The DEMS-DOSS study: validating a delirium monitoring tool in hospitalised older adults

Objective

to evaluate the sensitivity, specificity and test–retest reliability of the Delirium Early Monitoring System-Delirium Observation Screening Scale (DEMS-DOSS).

Design

prospective diagnostic accuracy study of a convenience sample of admitted older adults with DEMS-DOSS and reference standard assessments.

Setting

60-bed aged care precinct at a metropolitan hospital in Sydney, Australia.

Participants

156 patients (aged ≥65 years old) were recruited to participate between April 2018 and March 2020. One hundred participants were included in the analysis.

Measurements

Participants were scored on the DEMS-DOSS. Trained senior aged care nurses conducted a standardised clinical interview based on the Diagnostic and Statistical Manual of Mental Disorder (DSM)-IV delirium criteria, within two hours of DEMS-DOSS completion. The senior aged care nurse undertaking the DSM-IV interview was blinded to the results of the DEMS-DOSS.

Results

Participants’ mean age was 84 (SD ±7.3) years and 39% (n = 39) had a documented diagnosis of dementia. Delirium was detected in 38% (n = 38) according to the reference standard. The DEMS-DOSS had a sensitivity of 76.3% and a specificity of 75.8% for delirium. The area under the receiver operating characteristics curve for delirium was 0.76. The test–retest reliability of the DEMS-DOSS was found to be high (r = 0.915).

Conclusion

DEMS-DOSS is a sensitive and specific tool to assist with monitoring new onset and established delirium in hospitalised older adults. Further studies are required to evaluate the impact of the monitoring tool on health outcomes.

Terminal Delirium in Hospice: The Experiences and Perspectives of Caregivers Providing Care to Terminally Ill Patients in Home Settings

OBJECTIVES

Little is known about the experiences of caregivers who provide care to persons with terminal delirium (TD) in home settings. This scarcity of information is suggestive that further research is needed about care for hospice patients with delirium in the home and community.

AIM

To elicit views, feelings, and end-of-life care experiences of primary caregivers assisting dying persons with TD in hospice at home.

DESIGN

Qualitative, exploratory, cross-sectional study design was chosen. In-depth semistructured interviews explored caregiver experiences in caring for persons with TD. Qualitative thematic framework analysis was used.

PARTICIPANTS

Fifteen bereaved adult primary caregivers who received services from a hospice care program affiliated with a large nonprofit health system in the US Midwest.

RESULTS

Caregiver experiences were broad and reflected 4 major themes: symptomology, coping, effective and noneffective interventions, and support. The most distressing factors for caregivers were behaviors and symptomology of TD. They did not know what to say, how to respond, and how best to behave with someone who had delirium. Many caregivers had the impression that medication does not lessen delirium symptoms and that nonpharmacologic interventions are effective and beneficial only when they were important and meaningful to patients before delirium onset.

CONCLUSIONS

This study added new knowledge from direct and personal perspectives of caregivers providing end-of-life care to patients at home. Understanding developed about provision of care to someone with TD in home hospice. Improved comprehension of caregiver experiences can help professional hospice and palliative care staff better prepare caregivers for when patients have TD.

Consciousness and the rabbit holes of delirium

Delirium is a common disorder in hospitalized older adults and the defining characteristic is a disturbance of consciousness. Unfortunately, there are currently no testable measures of consciousness as pertains to its disruption in delirium. Not surprisingly rates of recognition of delirium suffer. Arguably, a greater understanding of the quantum of consciousness may improve delirium diagnosis through better diagnostic tools. Candidate dimensions of consciousness derived from fields of psychology, psychiatry, and philosophy are discussed and relevance to delirium explored. Based upon existing literature in the field of consciousness we identify the pre-reflective state, experiential awareness, and functional networks as candidate sites that may be affected in delirium. Opportunities for clinical instrument development and how these tools can be tested are discussed. We conclude that consciousness content may not hold to a unitary measurement, but facets of its integrity that are impacted in delirium are open to further exploration. Disorders in pre-reflective status, experiential awareness, and functional networks may represent the measurable "rabbit holes" of consciousness disturbance.

Delirium screening in patients in a palliative care ward: a best practice implementation project

OBJECTIVES

The objective was to promote evidence-based practice in screening for delirium in patients in the palliative care ward of a cancer hospital in Shanghai.

INTRODUCTION

Delirium is common but under recognized among patients in palliative care settings. Early detection is essential for timely management. Practice guidelines recommend an initial screening at first contact, followed by continuous screening.

METHODS

The Joanna Briggs Institute's three-phase Practical Application of Clinical Evidence System and the Getting Research into Practice audit and feedback tool were used to enhance evidence-based practice. In phase 1, four audit criteria were developed and a baseline audit was conducted. In phase 2, barriers to compliance were identified, and strategies were adopted to promote best practice. In phase 3, a follow-up audit was conducted.

RESULTS

In the baseline audit, no delirium screening was performed, either on admission or regularly during hospitalization, hence compliance with these two audit criteria was 0%. Two out of 18 nurses had received training in delirium management, however neither had been trained to use the delirium screening tool. Compliance with the two criteria for nurse training was 11% and 0%, respectively. Four barriers were identified, including lack of a standardized screening tool, lack of a standardized screening procedure, inadequate knowledge on the part of the nurses, and potential inconsistencies between nurses in the rating of screening criteria. After applying strategies to address these barriers, compliance with the four audit criteria was 100%, 100%, 72%, and 72%, respectively, in the follow-up audit.

CONCLUSIONS

Best practice in delirium screening was successfully established in the ward.

Differential clinical characteristics, management and outcome of delirium among ward compared with intensive care unit patients

BACKGROUND

Delirium is common in hospitalised patients but its epidemiology remains poorly characterised.

AIMS

To test the hypothesis that patient demographics, clinical phenotype, management and outcomes of patient with delirium in hospital ward patients differ from intensive care unit (ICU) patients.

METHODS

Retrospective cohort of patients admitted to an Australian university-affiliated hospital between March 2013 and April 2017 and coded for delirium at discharge using the International Classification of Diseases System, 10th revision, criteria.

RESULTS

Among 61 032 hospitalised patients, 2864 (4.7%) were coded for delirium. From these, we studied a random sample of 100 ward patients and 100 ICU patients. Ward patients were older (median age: 84 vs 65 years; P < 0.0001), more likely to have dementia (38% vs 2% for ICU patients; P < 0.0001) and less likely to have had surgery (24% vs 62%; P < 0.0001). Of ward patients, 74% had hypoactive delirium, while 64% of ICU patients had agitated delirium (P < 0.0001). Persistent delirium at hospital discharge was more common among ward patients (66% vs 17%, P < 0.0001). On multivariable analysis, age and dementia predicted persistent delirium, while surgery predicted recovery.

CONCLUSIONS

Delirium in ward patients is profoundly different from delirium in ICU patients. It has a dominant hypoactive clinical phenotype, is preceded by dementia and is less likely to recover at hospital discharge. Therefore, delirium prevention, detection and goals of care should be adapted to the environment in which it occurs.

Evaluating Mechanisms of Postoperative Delirium and Cognitive Dysfunction Following Elective Spine Surgery in Elderly Patients (CONFESS): Protocol for a Prospective Observational Trial

Background

Elderly people are at particular high risk for postoperative delirium (POD) following spine surgery, which is associated with longer hospital stays, higher costs, risk for delayed complications, long-term care dependency, and cognitive dysfunction (POCD). It is insufficiently understood which mechanisms and risk factors contribute to the development of POD and POCD following these major but plannable surgeries.

Objective

This study aims to identify modifiable risk factors in spine surgery. A better understanding thereof would help adapt medical management and surgical strategies to individual risk profiles.

Methods

This is a single-center observational study jointly conducted by the departments of neurosurgery, neurology, and anesthesiology at a tertiary care hospital in Germany. All patients aged 60 years and older presenting to the neurosurgery outpatient clinic or ward for elective spine surgery are screened for eligibility. Exclusion criteria include presence of neurodegenerative or history of psychiatric disease and medication with significant central nervous system activity (eg, antidepressants, antipsychotics, sedatives). Surgical and anesthetic procedures including duration of surgery as primary end point of this study are thoroughly documented. All patients are furthermore evaluated for their preoperative cognitive abilities by a number of tests, including the Consortium to Establish a Registry for Alzheimer's Disease Plus test battery. Physical, mental, and social health and well-being are assessed using the Patient-Reported Outcome Measurement Information System Profile 29 and Hospital Anxiety and Depression Scale. Patients additionally receive preoperative cerebrovascular ultrasound and structural and functional brain imaging. The immediate postoperative period includes screening for POD using the Nursing Delirium Screening Scale and validation through Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, criteria. We furthermore investigate markers of (neuro)inflammation (eg, interleukins, C-reactive protein, tumor necrosis factor alpha). Preoperative examinations are repeated 3 months postoperatively to investigate the presence of POCD and its mechanisms. Statistical analyses will compare delirious and nondelirious patients for predictors of immediate (POD) and delayed (POCD) cognitive dysfunction.

Results

This is the first study to prospectively evaluate risk factors for POD and POCD in spine surgery. Recruitment is ongoing, and data collection is estimated to be finished with the inclusion of 200 patients by mid-2020.

Conclusions

The identification of mechanisms, possibly common, underlying POD and POCD would be a major step toward defining effective interventional strategies early in or even before the postoperative period, including the adaptation of surgical strategies to individual risk profiles.

Trial Registration

ClinicalTrials.gov NCT03486288; https://clinicaltrials.gov/ct2/show/NCT03486288

Refining Delirium: A Transtheoretical Model of Delirium Disorder with Preliminary Neurophysiologic Subtypes

The development of delirium indicates neurophysiologic disruption and predicts unfavorable outcomes. This relationship between delirium and its outcomes has inspired a generation of studies aimed at identifying, predicting, and preventing both delirium and its associated sequelae. Despite this, evidence on delirium prevention and management remains limited. No medication is approved for the prevention or treatment of delirium or for its associated psychiatric symptoms. This unmet need for effective delirium treatment calls for a refined approach. First, we explain why a one-size-fits-all approach based on a unitary biological model of delirium has contributed to variance in delirium studies and prevents further advance in the field. Next, in parallel with the shift from dementia to "major neurocognitive disorder," we propose a transtheoretical model of "delirium disorder" composed of interactive elements-precipitant, neurophysiology, delirium phenotype, and associated psychiatric symptoms. We explore how these relate both to the biopsychosocial factors that promote healthy cognition ("procognitive factors") and to consequent neuropathologic sequelae. Finally, we outline a preliminary delirium typology of specific neurophysiologic disturbances. Our model of delirium disorder offers several avenues for novel insights and clinical advance: it univocally differentiates delirium disorder from the phenotype of delirium, highlights delirium neurophysiology as a treatment target, separates the core features of delirium from associated psychiatric symptoms, suggests how procognitive factors influence the core elements of delirium disorder, and makes intuitive predictions about how delirium disorder leads to neuropathologic sequelae and cognitive impairment. Ultimately, this model opens several avenues for modern neuroscience to unravel this disease of antiquity.

Effect of short-term exposure to ambient air particulate matter on incidence of delirium in a surgical population

Delirium remains an independent risk factor for morbidity and mortality among older surgical adults. Recent research has shed light on the relationship between pollution and dementia, yet little is known about the health impacts of particulate matter (PM) on delirium. Therefore, we aim to further explore association of PM and delirium among surgical population. We conducted a time-stratified case-crossover study. Electronic hospitalization summary reports derived from 26 major cities in China between 1 January 2014 and 31 December 2015 were used. Conditional logistic regression were applied to explore the association between perioperative PM exposure and delirium. A total of 559 surgical patients with delirium were identified. Both PM2.5 and SO₂ on the day of surgery had a negative impact, with an interquartile range (IQR) increase in PM2.5 (47.5 μg/m³) and SO₂ (22.2 μg/m³) significantly associated with an 8.79% (95% confidence interval [CI], 0.01–18.47%, P < 0.05) and 16.83% (95% CI, 0.10–36.35%, P < 0.05) increase in incidence of delirium, respectively. PM on other days during the perioperative period showed no significant impact. The present study showed that short-term exposure to ambient air PM on the day of surgery increased the incidence of delirium in a surgical population during hospitalization.